Referring to FIG. 1, a conventional decorative amusement device 1 is shown to include a base 11, a transparent sphere 12 that is mounted on the base 11 and that cooperates therewith so as to confine a water receiving space 121 to be filled with water, and a drive unit 13 mounted inside the base 11. The drive unit 13 includes a motor 131 with a rotary drive shaft 130 that extends through the base 11 and into the water receiving space 121. A water agitator 133 is mounted on the drive shaft 130 inside the water receiving space 121, and is driven rotatably by the drive shaft 130 to agitate the water inside the water receiving space 121, thereby causing the water and glittering specks to circulate inside the water receiving space 121 in order to provide an aesthetic effect.
A disadvantage of the aforesaid conventional decorative amusement device resides in that no movable objects are mounted inside the water receiving space 121. The water circulation by itself will eventually provide a monotonous feeling upon long term use of the conventional device.